The invention is directed to improvements in fuel injection pumps.
In a fuel injection pump of this type, known from German Pat. No. 1 035 970, the distributor merges, at its end that protudes out of the distributor cylinder on the drive side of the distributor, with a part having an enlarged diameter, in which the pump cylinders and pump pistons are disposed. This part includes the cam ring, on which roller tappets roll on its cam track that points radially inward; the roller tappets cause the pump pistons to execute a reciprocating movement. To this end, the distributor is driven by a pump drive shaft in synchronism with the rpm of the associated internal combustion engine. The drive shaft is integral with the distributor and disposed coaxially thereto. On the part of this shaft adjoining the part of the distributor having the enlarged diameter, there is an annular slide which has relief bores, each of which cooperate with triangular control openings on the jacket face of the distributor. These control openings communicate with the relief conduit. The annular slide is both axially displaceable and rotatable on the distributor by means of control members, and it is coupled with the cam ring via a bar in order to rotate the cam ring.
This fuel injection pump has the disadvantage that the annular slide is located between the part of the distributor having the pump pistons and the drive shaft. The distributor part on which the annular slide operates must therefore transmit the large drive moment for actuating the pump pistons and is exposed to oscillating forces in accordance with the number of cams on the cam track of the cam ring or the number of pumping strokes per revolution of this radial piston distributor pump. This distributor part must furthermore have a relatively large diameter. Because the rotation of the cam ring is effected via the annular slide, there are harmful consequences here too, which substantially affect the accuracy of control.